1. Field of the Invention
The present invention relates to a thin film transistor-liquid crystal display (hereinafter referred to as a TFT-LCD) and a manufacturing method therefor. More particularly, this invention relates to a TFT-LCD and a manufacturing method therefor which etches multi-layer patterns in a single process step.
2. Description of the Related Art
A conventional TFT-LCD is disclosed in Society for Information Display '94 DIGEST, page 263, the content of which is hereby expressly incorporated by reference herein in its entirety. That TFT-LCD will now be described with reference to FIGS. 1, 2A–2H, and 3A–3H.
In FIG. 1, a conventional TFT-LCD is depicted which comprises: a substrate 1, a gate electrode 2, an anodic oxidation layer 3, an insulating layer 4, an amorphous silicon layer 5, an n+ amorphous silicon layer 6, a source/drain electrode 9, a passivation layer 10, and a pixel electrode layer 13.
FIGS. 2A–2H show several cross-sectional views depicting different stages of a fabrication sequence for the conventional TFT-LCD shown in FIG. 1. FIGS. 3A–3H show cell views of layouts corresponding to the steps illustrated in FIGS. 2A–2H, respectively. Some layers are omitted from the cell layout views of FIGS. 3A–3H for purposes of simplification. Referring to those figures, a conventional method for fabricating a TFT-LCD generally comprises the steps of:
forming a gate pad 21, a gate electrode 2, and a gate line by depositing and etching a metal layer on a substrate 1;
forming a anodic oxidation layer 3 on both the gate electrode 2 and a portion of the gate pad 21;
depositing an insulating layer 4;
depositing an amorphous silicon layer 5 on the insulating layer 4;
depositing an n+ amorphous silicon layer 6 on the amorphous silicon layer 5;
etching both the amorphous silicon layer 5 and the n+ amorphous silicon layer 6 to form an active island 56;
partially etching the insulating layer 4 on the gate pad 21;
forming both a source/drain electrode 9 and a data line by depositing and etching a metal layer;
forming a passivation layer 10 having a contact hole 12 by depositing and etching an insulating material; and
forming a pixel electrode 13 by depositing and etching a transparent conductive material.
The above-described conventional TFT-LCD has many problems.
First, it reduces production yield. In addition, the etchants used during the etching process steps cause defects in the resulting TFT-LCD.
Moreover, it is more costly because many etching processes are employed in its fabrication.